The present embodiments relate to industrial processes. More specifically, the present embodiments relate to industrial process field devices for use in monitoring or control of industrial processes.
Field devices, such as process variable transmitters, used in industrial processes can be installed in the field on pipelines, tanks and other industrial process equipment. These devices sense process variables such as process fluid flow, process fluid temperature, process fluid pressure, process fluid conductivity, process fluid pH and other process variables. Other types of industrial process field devices include valves, actuators, field controllers, data displays and communication equipment such as industrial field network bridges.
One type of process variable sensor is a flow meter that can measure a rate of fluid flow, for example. One type of flow meter, which employs an averaging pitot tube, is a popular device for flow measurement because of its ability to be inserted into and retracted from a flow line, its low pressure loss, relatively low cost and reliable performance. However, measurement inaccuracies can occur in such flow meters when there are disturbances in flow conditions. The disturbances in flow conditions can be caused by, for example, pipe elbows, reducers, expanders, valves or similar irregularities. Typically, flow disturbances can be conditioned by relatively long runs of straight pipe (for example, up to 30 diameters of straight pipe) upstream of the flow meter such that the flow meter can deliver substantially accurate results.
In some applications where only minimal straight pipe length is available upstream of a flow meter installation, permanent flow conditioners having elements that reduce flow turbulence may be used to improve accuracy of flow meter measurements. However, a permanent flow conditioner is a permanent obstruction in the pipe, which can complicate pipe maintenance operations such as cleaning. Further, permanent flow conditioners can cause pressure loss to the piping system.